feat(forge): add gas reports for tests

[brockelmore]

Adds --gas-report flag to forge test.

Adds gas_reports into foundry.toml which lets the user specify which contracts they want gas reports for, i.e:

gas_reports = ["MyContract", "MyContractFactory"]

or to produce a report for everything:

gas_reports = ["*"]

then if the user does forge test --gas-report they will get an output like:

Note: the colors you see here are a bit different than what may show up for you. My terminal theme is a bit off and it shows green as yellow and yellow as green.

Partially addresses #137

[mattsse]

great!

[brockelmore]

note: we dont current include calldata costs in this snapshot - we could change how we calculate gas in call traces to include calldata costs to make it more realistic for an EOA to call a function

[onbjerg]

another banger by brock

[gakonst]

very nice

[fubhy]

Awesome. I think it may be useful to also include the name of the test that caused the max gas cost. Would that be easy to add as a column?

[brockelmore]

Awesome. I think it may be useful to also include the name of the test that caused the max gas cost. Would that be easy to add as a column?

ye just keep parent CallArenaTrace decoded function name in the GasReport and replace as you see a max value. I don't want to support this right now though because thats actually a slightly different usecase than high level gas usage reports